The present invention relates to toy water shooters. More particularly, although not exclusively, the invention relates to a toy water pistol having a special pulse-firing feature.
A typical inexpensive known toy water pistol 10 is depicted in FIGS. 1 and 2. The water pistol 10 includes a trigger 21 which when squeezed causes firing of a jet of water via nozzle 11. The toy water pistol includes a cylinder 18 in which there is a reciprocal piston 20 connected to the trigger 21. There is a water-tight seal 19 between the piston 20 and the internal wall of cylinder 18. A piston return spring 14 biases the piston 20 and trigger 21 to an extended position. Water from an internal reservoir (not shown) is delivered though a water duct 15 to the cylinder 18 via an inlet valve 17 which is biased into a closed position by an inlet valve spring 16. Water is delivered from the cylinder 18 to the nozzle 11 via an outlet valve 13 which is biased into a closed position by outlet valve spring 12. Upon squeezing of trigger 21, the piston 20 and seal 19 move to pressurize the water within the cylinder 18. This pressure causes the outlet valve 13 to open against the force of spring 12. When the trigger 21 is released, the piston return spring 14 biases the piston 20 and trigger 21 to the rest position whereupon outlet valve 13 closes and inlet valve 17 opens to allow the ingress of water via the water inlet duct 15 to replenish the cylinder 18 with water.
The water-shooting distance will depend upon how rapidly the player squeezes the trigger. For a given nozzle exit hole size, rapid squeezing of the trigger will cause the water jet to fire further, however if the trigger is squeezed slowly, the lower pressure generated inside the cylinder 18 will result in a shorter firing distance.
During squeezing of the trigger 21, the piston 20 tends to pressurize water in the cylinder 18, however as the water jet is concurrently emitted from the nozzle 11, this tends to relieve pressure in the cylinder 18.
The size of the exit hole at nozzle 11 will affect the shooting distance. If the nozzle hole diameter is small, nozzle-induced back-pressure will be high and so the rate of pressure drop in the cylinder 18 will be low—resulting in the water pressure inside the cylinder 18 being maintained at a relatively high level. However the resultant thin water jet will have insufficient momentum to fire a long distance.
On the other hand, if the exit hole at nozzle 11 is large, the water jet can be thicket and thereby have higher momentum to enable shooting over a long distance. A disadvantage however is that the nozzle-induced back-pressure in the cylinder 18 is low and so the rate of pressure drop in the cylinder 18 is high. As a result, a long firing distance cannot be achieved unless the player squeezes the trigger hard and fast.
Usually the players of such known water pistols are young children who cannot squeeze the trigger rapidly or apply the necessary dexterity to fire a good long-distance water jet.